<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title>计算器</title>
	</head>
	<body>
		
		<input type="text" id="num1">
	    <select name="" id="symbol">
			<option value="1">+</option>
			<option value="2">-</option>
			<option value="3">*</option>
			<option value="4">/</option>
		</select>
		<input type="text" id="num2">
		=<input type="text" id="num3">
		<button onclick="abc()">提交</button>
		<button onclick="a()">重置</button>
		</form>
		<script type="text/javascript">
			var one=document.getElementById('num1').value;
			var symbo=document.getElementById('symbol').value;
			var two=document.getElementById('num2').value;
			var aa=0;
			function abc(){
				switch (symbo){
				case '1':
					aa=(parseFloat(one)+parseFloat(two));
				break;
				case '2':
				    aa=(parseFloat(one)-parseFloat(two));
				break;
				case '3':
				    aa=(parseFloat(one)*parseFloat(two));
				break;
				case '4':
				    aa=(parseFloat(one)/parseFloat(two));
				break;
			} 
			    num3.value=aa;
			}
			function a(){
				location.reload;
			} 
		</script>
	</body>
</html>
